Identification of critical TF-miRNA-mRNA regulation loops for colorectal cancer metastasis.

To explore the potential cause of colorectal cancer metastasis, gene expression profiles, GSE21510, and miRNA expression profiles, GSE48074, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes in metastatic colorectal and non metastatic colorectal cancer compared with the normal samples were identified via the limma package in R. The differentially expressed miRNAs in colorectal cancer samples with lymph node metastasis compared with those without lymph node metastasis were screened out by the some method. Differentially expressed genes that were upregulated in colorectal cancer samples with distant metastasis in comparison to that in samples without distant metastasis and normal samples were considered to play important roles in colorectal cancer metastasis. Functional enrichment analysis of these genes was conducted using the Database for Annotation, Visualization, and Integrated Discovery v6.7. Biological processes related to cell differentiation and cell proliferation were significantly enriched. TF (transcription factor)-miRNA-mRNA regulation loops were constructed by using the starBase and ChIPBase databases. Finally, six critical regulation loops were screened out. They were composed of two TFs, two miRNAs, and three mRNAs. Some of these TFs, mRNAs, or miRNAs have previously been identified as critical targets in colorectal cancer metastasis. Additionally, several new targets were identified in our study, which may be helpful to improve metastatic colorectal cancer treatment.

A portable molecular beam epitaxy system for in situ x-ray investigations at synchrotron beamlines.

A portable synchrotron molecular beam epitaxy (MBE) system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, reflection high energy electron diffraction setup, and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate its performance by investigating the annealing process of buried InGaAs self-organized quantum dots.

Quantification of sample thickness and in-concentration of InGaAs quantum wells by transmission measurements in a scanning electron microscope.

High-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images of electron-transparent samples show dominant atomic number (Z-) contrast with a high lateral resolution. HAADF STEM at low electron energies <30 keV is applied in this work for quantitative composition analyses of InGaAs quantum wells. To determine the local composition, normalized experimental image intensities are compared with results of Monte Carlo simulations. For verification of the technique, InGaAs/GaAs quantum-well structures with known In concentration are used. Transmission electron microscopy samples with known thickness are prepared by the focused-ion-beam technique. The method can be extended to other material systems and is particularly promising for the analysis of materials that are sensitive toward knock-on damage.

[The changes in glucocorticoid receptors in peripheral leukocytes in asthmatic subjects].

The number of glucocorticoid receptors (GCR) in peripheral leukocytes was determined by radioligand-binding assay in extrinsic and intrinsic asthmatics. Their corresponding plasma cortisol levels were assessed. The results showed that the average number of GCR in asthmatics was significantly lower than that in healthy subjects (P < 0.01), and there was a linear correlation between the number of GCR and the course of asthma. Besides, there was also a linear correlation between the number of GCR and the age of the initial attack of asthma. No difference in plasma cortisol level was found between asthmatics and healthy subjects. These findings suggest that there is no primary and general impairment of glucocorticoid metabolism in the asthmatics, but the number of GCR in the asthmatics is lower than that in healthy controls. The decrease of the number of GCR in asthmatics, we think, is related to heredity and repeated attacks of asthma.